Electric vehicles, including, but not limited to, hybrid vehicles, employ a high voltage electric battery system that includes a number of battery cells. An electric vehicle typically requires several battery cells to provide enough power to meet vehicle power and energy requirements. The battery cells are generally grouped into packs, and a plurality of battery packs form an energy storage system (ESS), which may be rechargeable. The ESS is often located under the vehicle body midway between the front and rear wheels.
Electric vehicles also often include a low voltage battery, such as a 12-volt battery, that powers one or more auxiliary systems, including, but not limited to, headlights, windshield wipers, power door locks, power seats, an audio system, and other electronic components. The low voltage battery may be recharged by the ESS via an auxiliary power module (APM), which may be electrically connected to the low voltage battery. The APM is a DC-DC power converter that converts power from the high voltage of the ESS to the low voltage required by the low voltage battery. The APM is often located in the trunk or other storage compartment of the vehicle.
Both the ESS and the APM may generate thermal energy during operation, and as such, may require cooling in order to maximize the charging capacity and life of the batteries. Additionally, external temperatures near the ESS and the APM due to their respective locations may further affect operating efficiency. Cooling systems, which may include circulation of a coolant through cooling plates, have been developed to provide cooling for individual battery cells in the ESS and to the external sides of the APM. These cooling systems may require tubing and additional devices to provide the desired temperature control.